Refrigerant compressor and pressure-resistant vessel

ABSTRACT

A refrigerant compressor improved in pressure-resistant strength of a closed vessel. In a prior-art refrigerant compressor, a three-phase integral type sealed terminal in which three pins connected to a three-phase power source are disposed on one metal base portion, is attached to a body portion of a closed vessel for supplying electric power to an electric motor. When a high hydrostatic pressure load is applied to the closed vessel, the closed vessel is deformed into a barrel shape, and the sealed terminal pulled in the circumferential direction due to the deformation of the closed vessel is deformed elliptically. There may arise a problem with a glass material for insulating the metal base portion from the pins.  
     To solve the problem, three small-diameter sealed phase terminals independent of one another are disposed in a body portion of a closed vessel for supplying electric power to an electric motor unit. The terminals are aligned substantially in a line in the circumferential direction of the body portion of the closed vessel.

FIELD OF THE INVENTION

[0001] The present invention relates to a closed vessel for a refrigerant compressor and a pressure-resistant vessel, and particularly relates to the improvement of the pressure-resistant strength of a closed vessel for a refrigerant compressor and the improvement of the pressure-resistant strength of a pressure-resistant vessel.

BACKGROUND OF THE INVENTION

[0002]FIG. 7 shows a scroll compressor as an example of a prior-art refrigerant compressor.

[0003] In FIG. 7, a closed vessel 10 is constituted by a cylindrical body portion 10 d, an upper end cover 10 e and a lower end cover 10 f. A compression mechanism unit 1 and an electric motor unit 7 are disposed in the closed vessel 10. Both the units are connected to each other through a drive shaft 8. In the compression mechanism unit 1, a low-pressure refrigerant gas taken in through a suction pipe 3 is compressed by use of rotation given from the electric motor unit 7 through the drive shaft 8. The refrigerant gas brought thus into a high pressure state is discharged into the closed vessel 10 through a discharge port 1 f. The closed vessel 10 in which the electric motor unit 7 is disposed, is filled with the high pressure refrigerant gas so that a high pressure atmosphere is produced in the closed vessel 10. The high pressure refrigerant gas is discharged into a refrigerating cycle outside the closed vessel through a discharge pipe 4 disposed in the body portion 10 d of the closed vessel 10. In addition, a sealed terminal 5 is disposed in the body portion 10 d of the closed vessel 10. The electric motor unit 7 is supplied with electric power through the sealed terminal 5.

[0004]FIGS. 8A and 8B are main portion sectional views showing the state where the sealed terminal is attached to the closed vessel. FIG. 8A illustrates a section viewed from a side of the sealed terminal 5. FIG. 8B illustrates a section viewed from the front likewise.

[0005] In FIGS. 8A and 8B, the sealed terminal 5 has a structure in which three pins 5 b are disposed on a circular metal base portion 5 a, and the respective pins and the metal base portion are electrically insulated from one another by glass sealing with glass 5 c. The sealed terminal 5 is electrically welded to an attachment hole 10 a provided in the outer wall of the body portion 10 d of the closed vessel 10. The attachment hole 10 a has a diameter substantially equal to that of the metal base portion 5 a. Thus, the sealed terminal 5 is designed to ensure the airtightness between the inside and outside of the closed vessel 10.

[0006] Next, description will be made about the attachment of the suction pipe 3 and the discharge pipe 4 to the closed vessel 10.

[0007]FIG. 9 is a main portion sectional view showing the state where the suction pipe 3 is attached to the closed vessel 10.

[0008] In FIG. 9, a joint pipe 3 a is braze-welded and attached to an attachment hole 10 b formed in the body portion 10 d of the closed vessel 10. An outside pipe 3 b is inserted into the inside of the joint pipe 3 a up to a suction port 1 a of the compression mechanism unit. Then, an inside pipe 3 c is further attached to the inside of the outside pipe 3 b by press fitting. The outer circumference of the outside pipe 3 b is pressed and expanded by the press fitting of the inside pipe 3 c so as to come into close contact with the inner circumference of the suction port 1 a of the compression mechanism unit. Thus, the airtightness between the inside and outside of the closed vessel can be kept.

[0009] The suction pipe 3 is inserted into the outside pipe 3 b, and braze-welded to the joint pipe 3 a and the outside pipe 3 b simultaneously. Thus, the suction pipe 3 is designed to keep the airtightness between the inside and outside of the closed vessel 10.

[0010]FIG. 10 is a main portion sectional view showing the state where the discharge pipe 4 is attached to the closed vessel 10.

[0011] In FIG. 10, a joint pipe 4 a is braze-welded to an attachment hole 10 c formed in the body portion 10 d of the closed vessel 10 in the same manner as the suction pipe 3. The discharge pipe 4 is inserted into the inside of the joint pipe 4 a, and brazed thereto. Thus, the discharge pipe 4 is designed to keep the airtightness between the inside and outside of the closed vessel 10.

[0012] In the prior-art refrigerant compressor, a three-phase power supply was attached to the body portion 10 d of the closed vessel 10 in the form of the comparatively large-diameter sealed terminal 5 disposed on the metal base portion 5 a. Accordingly, when the closed vessel 10 was filled with a high pressure gas, particularly when the pressure in the closed vessel 10 increased to an abnormally high pressure for some reason, the sealed terminal attaching hole 10 a might be deformed elliptically. In the worst case, there might arise a trouble in the welded portion of the sealed terminal 5 due to the pressure stress.

[0013] In addition, when a high hydrostatic pressure load was applied to the closed vessel 10 in a hydrostatic pressure overload test for securing a safety standard, there was a case where a given standard pressure could not be cleared. That is, the closed vessel 10 was deformed into a barrel-like shape, and the sealed terminal 5 pulled in the circumferential direction accordingly with the deformation of the closed vessel 10 was deformed elliptically. Thus, the glass 5 c for insulating the metal base portion 5 a from the pins 5 b was cracked and broken.

[0014]FIGS. 11A to 11C show the circumstances in which the closed vessel and the sealed terminal are deformed in a hydrostatic pressure overload test. FIG. 11A is an exterior view showing the deformation of the closed vessel. FIG. 11B is a sectional view showing the deformation of the sealed terminal. FIG. 11C is a view showing the deformation of the circular metal base portion. With the barrel-like deformation of the closed vessel 10, the sealed terminal attaching hole 1 a is also pulled in the circumferential direction and deformed elliptically. With the deformation of the sealed terminal attaching hole 10 a, the sealed terminal 5 is pulled accordingly and deformed elliptically. At the same time, the sealed terminal 5 suffers the hydrostatic pressure from the inside of the closed vessel 10 so as to be pushed outwardly. The glass 5 c for insulating the metal base portion 5 a from the pins 5 b cannot accommodate the plastic deformation of the metal base portion 5 a. Thus, the glass 5 c is cracked and broken. In addition, when the deformation of the sealed terminal attaching hole 10 a is great, the close contact between the sealed terminal 5 and the electrically welded portion in the outer circumference of the sealed terminal 5 may be broken to cause destruction.

[0015] In addition, in the prior-art refrigerant compressor, the suction pipe 3 and the discharge pipe 4 were attached to the body portion 10 d of the closed vessel 10. Accordingly, when the closed vessel 10 was filled with a high pressure gas, particularly when the pressure in the closed vessel 10 increased to an abnormally high pressure for some reason, the attachment holes 10 b and 10 c for the respective joint pipes 3 a and 4 a of the suction pipe 3 and the discharge pipe 4 might be deformed elliptically. In the worst case, there might arise a problem in the welding due to the pressure stress.

[0016] In addition, in a hydrostatic pressure overload test for securing a safety standard, there was a case where a given standard pressure could not be cleared. That is, the closed vessel 10 was deformed into a barrel-like shape, and the joint pipe attaching holes 10 b and 10 c pulled in the circumferential direction accordingly with the deformation of the closed vessel 10 were deformed elliptically. Thus, the welded portions were cracked and broken.

[0017]FIG. 12 shows the attachment portion of the suction pipe 3 to the closed vessel 10 subjected to a hydrostatic pressure overload test. With the barrel-like deformation of the closed vessel 10, the attachment hole 10 b for the suction pipe 3 is pulled accordingly in the circumferential direction so as to be deformed elliptically. When the deformation further goes on, the welded portion between the outer circumference of the joint pipe 3 a and the attachment hole 10 b is cracked and broken. The circumstances when the discharge pipe is broken are similar to those in the case of the suction pipe in FIG. 12.

SUMMARY OF THE INVENTION

[0018] The present invention has been made to solve the foregoing problems. An object of the invention is to improve the pressure-resistant strength of a closed vessel in a refrigerant compressor of a so-called high pressure shell system.

[0019] Another object of the invention is to improve the pressure-resistant strength of a sealed terminal attaching portion or portions of the closed vessel.

[0020] Another object of the invention is to improve the pressure-resistant strength of a suction pipe attaching portion and a discharge pipe attaching portion of the closed vessel.

[0021] Another object of the invention is to improve the pressure-resistant strength of a pressure-resistant vessel.

[0022] Another object of the invention is to improve the pressure-resistant strength of a sealed terminal attaching portion or portions of the pressure-resistant vessel.

[0023] Another object of the invention is to improve the pressure-resistant strength of a pipe attaching portion or portions of the pressure-resistant vessel.

[0024] In the refrigerant compressor defined in Claim 1, three sealed terminals for supplying electric power to an electric motor of an electric motor unit are each attached to a closed vessel independently of one another for every phase.

[0025] In the refrigerant compressor defined in Claim 2, the three phase terminals each attached to the closed vessel independently of one another for every phase are aligned substantially in a line in a circumferential direction of a body portion of the closed vessel.

[0026] In the refrigerant compressor defined in Claim 3, at least one of a suction pipe for sucking a refrigerant and a discharge pipe for discharging the refrigerant after compression is attached to an attachment hole formed in an attachment hole formation portion of a closed vessel with a front end portion thereof subjected to burring.

[0027] In the refrigerant compressor defined in Claim 4, three sealed terminals for supplying electric power to an electric motor of an electric motor unit are each attached to a closed vessel independently of one another for every phase, while at least one of a suction pipe and a discharge pipe is attached to an attachment hole formed in an attachment hole formation portion of the closed vessel with a front end portion thereof subjected to burring.

[0028] In the refrigerant compressor defined in Claim 5, at least one sealed terminal for supplying electric power to an electric motor of an electric motor unit is attached to an attachment hole formed in an attachment hole formation portion of a closed vessel with a front end portion thereof subjected to burring. Either three sealed phase terminals or a three-phase integral type sealed terminal may be used.

[0029] The pressure-resistant vessel defined in Claim 6 is a pressure-resistant vessel for receiving an electric motor unit, wherein sealed terminals for supplying three-phase electric power to an electric motor unit are each attached to the pressure-resistant vessel independently of one another for every phase.

[0030] The pressure-resistant vessel defined in Claim 7 contains at least one of a pipe for introducing a fluid into the pressure-resistant vessel and a pipe for extracting the fluid from the pressure-resistant vessel, the pipe being attached to an attachment hole formed in an attachment hole formation portion of the pressure-resistant vessel with a front end portion thereof subjected to burring.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1 is a longitudinal sectional view of a scroll compressor according to a first embodiment of the invention;

[0032]FIGS. 2A to 2C are views for explaining the sealed terminals in the first embodiment of the invention;

[0033]FIGS. 3A and 3B are a graph and a view explanatorily showing the breaking strengths of closed vessels to which the sealed terminal or terminals have been attached in a hydrostatic pressure overload test according to the first embodiment of the invention;

[0034]FIG. 4 is an explanatory view showing the state where the suction pipe is attached to the closed vessel according to the first embodiment of the invention;

[0035]FIG. 5 is an explanatory view showing the state where the discharge pipe is attached to the closed vessel according to the first embodiment of the invention;

[0036]FIG. 6 is a graph explanatorily showing the breaking strengths of the closed vessels to which the suction pipe has been attached in a hydrostatic pressure overload test according to the first embodiment of the invention;

[0037]FIG. 7 is a longitudinal sectional view of a prior-art scroll compressor;

[0038]FIGS. 8A and 8B are main portion sectional views showing the state where the sealed terminal is attached to the closed vessel in the prior art;

[0039]FIG. 9 is a main portion sectional view showing the state where the suction pipe is attached to the closed vessel in the prior art;

[0040]FIG. 10 is a main portion sectional view showing the state where the discharge pipe is attached to the closed vessel in the prior art;

[0041]FIGS. 11A to 11C are views showing the circumstances in which the closed vessel and the sealed terminal are deformed when a hydrostatic pressure overload test was conducted on the closed vessel in the prior art; and

[0042]FIG. 12 is a view showing the attachment portion for the suction pipe when the hydrostatic pressure overload test was conducted on the closed vessel in the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0043] First Embodiment

[0044]FIG. 1 is a longitudinal sectional view of a scroll compressor as an example of a refrigerant compressor according to a first embodiment of the invention.

[0045] In FIG. 1, a closed vessel 10 is constituted by a cylindrical body portion 10 d, an upper end cover 10 e and a lower end cover 10 f. A compression mechanism unit 1 and an electric motor unit 7 are received in the closed vessel 10. The compression mechanism unit 1 has a fixed scroll, a rocking scroll, and so on. The electric motor unit 7 has an electric motor constituted by a stator and a rotor. Both the units are connected to each other through a drive shaft 8. In the compression mechanism unit 1, a low-pressure refrigerant gas taken in through a suction pipe 3 is compressed by use of the rotation given from the electric motor unit 7 through the drive shaft 8. The refrigerant gas brought thus into a high pressure state is discharged into the closed vessel 10 through a discharge port 1 f. The closed vessel 10 in which the electric motor unit 7 is disposed, is filled with the high pressure refrigerant gas so that a high pressure atmosphere is produced in the closed vessel 10. This refrigerant gas is discharged into a refrigerating cycle outside the closed vessel 10 through a discharge pipe 4 disposed in the body portion 10 d of the closed vessel 10.

[0046] Three small-diameter sealed terminals 6 (one of them is shown in FIG. 1) are disposed in the body portion 1 d of the closed vessel 10. The electric motor unit 7 is supplied with three-phase electric power through the sealed terminals 6.

[0047] In addition, attachment hole formation portions in the outer wall of the closed vessel 10 to which the suction pipe 3 and the discharge pipe 4 are attached are subjected to burring (each burred or deburred portion is specified by the reference numeral 12 in FIG. 1). Each of the attachment hole formation portions is thicker than any other outer wall portion.

[0048] The other constituent members are similar to those of FIG. 7 for the prior art, and referenced correspondingly. Description of those constituent members will be therefore omitted.

[0049]FIGS. 2A to 2C are views for explaining the sealed terminals in the first embodiment of the invention. FIG. 2A is a sectional view of the sealed terminal. FIG. 2B is a schematic layout view showing the pins of the sealed terminals aligned in a single transverse line. FIG. 2C is a schematic layout view showing the pins of the sealed terminals located in angular positions.

[0050] In FIGS. 2A to 2C, as the sealed terminals 6 in this embodiment, three phase terminals 6 each having a smaller diameter than the three-phase integral type sealed terminal 5 in the prior art are disposed in the closed vessel 10.

[0051] Each phase terminal 6 has a structure in which a single pin 6 b connected to one of the three phases of a power supply is disposed on a small-diameter circular metal base portion 6 a, and the pin 6 b and the metal base portion 6 a are electrically insulated from each other by glass sealing with glass 6 c. The phase terminal 6 is electrically welded to an attachment hole 10 a provided in the outer wall of the body portion 10 d of the closed vessel 10. The attachment hole 10 a has a diameter substantially equal to that of the metal base portion 6 a. Thus, the phase terminal 6 is designed to ensure the airtightness between the inside and outside of the closed vessel 10.

[0052] As for the method of arranging the three phase terminals 6, the phase terminals 6 may be aligned in a line in the circumferential direction of the closed vessel 10 as shown in FIG. 2B, or located in the angular positions of an equilateral triangle as shown in FIG. 2C.

[0053] Each sealed terminal 6 (phase terminal 6) is arranged to have a small diameter in such a manner. Thus, the terminal attaching hole 10 a can be restrained from being deformed elliptically due to the barrel-like deformation of the closed vessel 10. In addition, since the sealed terminal 6 itself becomes smaller, its rigidity increases. Thus, the sealed terminal 6 is restrained from swelling out due to the internal pressure, so that the stress of the metal base portion 6 a and the pin 6 b on the insulating glass 6 c is reduced. As a result, both the pressure-resistant strength of the sealed terminals and the pressure-resistant strength of the attachment portions involved in the phase terminals 6 increase so as to lead to the improvement of the pressure-resistant strength of the closed vessel 10 as a whole.

[0054]FIG. 3A shows the breaking strength of the closed vessel 10 in a hydrostatic pressure overload test conducted when such sealed terminals 6 have been attached (the hydrostatic pressure overload test conducted in a condition that no load was applied to the suction pipe attaching portion and the discharge pipe attaching portion). FIG. 3A shows, in comparison, the breaking strength in the case of the three-phase integral type sealed terminal 5 in the prior art, the breaking strength in the case of the three phase terminals 6 aligned in a single transverse line, and the breaking strength in the case of the three phase terminals 6 located in the angular positions of an equilateral triangle.

[0055] While the breaking strength in the case of the three-phase integral type sealed terminal 5 in the prior art was 18 MPa in hydrostatic pressure, the breaking strength in the case of the sealed terminals 6 in this embodiment was 25 MPa. Thus, a strength improvement of about 40% could be obtained. On the other hand, as for the manner to arrange the phase terminals 6, the pressure-resistant strength in the case of the three phase terminals 6 aligned in a line in the circumferential direction was 25 MPa while the pressure-resistant strength in the case of the three phase terminals 6 located in the angular positions of an equilateral triangle was 22 MPa, which was lower than 25 MPa in the former case.

[0056] In this breaking in the case of the three phase terminals 6 located in the angular positions, a crack 11 was produced between the terminal attaching holes 10 a different in axial height as shown in FIG. 3B. This fact suggests that the attachment holes 10 a are preferably attached horizontally in the circumferential direction. However, even in the case of the three phase terminals 6 located in the angular positions, the strength increases in comparison with the case of the three-phase integral type sealed terminal 5 in the prior art.

[0057] Incidentally, the manner to arrange the three phase terminals 6 in the closed vessel is not limited to the above-mentioned two arrangement cases. An excellent result can be obtained when the three phase terminals 6 are arranged conveniently for the connection to a three-phase power supply, and at a balanced distance, that is, at a distance not too close to one another and not too far from one another for the purpose of securing the strength.

[0058]FIGS. 4 and 5 are explanatory views showing the states where the suction pipe and the discharge pipe are attached to the body portion 10 d of the closed vessel 10 in FIG. 1, respectively.

[0059] In FIGS. 4 and 5, the attachment hole formation portions for forming the attachment holes 10 b and 10 c in the closed vessel 10 have their front end portions subjected to burring so as to be portions for attaching joint pipes 3 a and 4 a for the suction pipe 3 and the discharge pipe 4 to the closed vessel 10 (each burred portion is specified by the reference numeral 12 in FIGS. 4 and 5), thus forming the attachment holes 10 b and 10 c.

[0060] Since the burring is performed, the vicinities (attachment hole formation portions) of the attachment holes 10 b and 10 c for the joint pipes 3 a and 4 a can be made thicker than any other outer wall portion of the closed vessel. Accordingly, the attachment holes 10 b and 10 c can be restrained from being deformed elliptically due to the barrel-like deformation of the closed vessel 10. The welding with the joint pipes 3 a and 4 a can be also restrained from cracking. Thus, the burring is useful in improving the pressure-resistant strength of the closed vessel 10.

[0061] Incidentally, when the attachment hole front end portions are bent outward so as to increase the thickness in the front end portions, and the suction pipe 3 and the discharge pipe 4 are then attached thereto, the effects substantially similar to those in the case of the burring can be obtained.

[0062]FIG. 6 shows the comparison in the hydrostatic pressure overload test results (the hydrostatic pressure overload test conducted in a condition no load was applied to the sealed terminal attaching portion(s) and the discharge pipe attaching portion) between the pressure-resistant strength of the closed vessel 10 in which the suction pipe 3 was attached to the attachment hole 10 b subjected to burring and the pressure-resistant strength of the prior-art closed vessel 10 subjected to no burring.

[0063] Because the attachment hole 10 b for the joint pipe 3 a was improved in strength by the burring so as to be restrained from being deformed elliptically, the pressure-resistant strength in this embodiment was 25 MPa in hydrostatic pressure while that in the prior art was 20 MPa likewise. Thus, a pressure-resistant strength improvement of about 25% could be obtained.

[0064] As for the discharge pipe 4, the similar results of the hydrostatic pressure overload test could be obtained.

[0065] Incidentally, because the attachment hole formation portions are increased in thickness by the burring, sufficient pressure-resistant strength can be obtained even if the suction pipe 3 and the discharge pipe 4 are attached to the attachment holes 10 b and 10 c directly without interposition of the joint pipes 3 a and 4 a, respectively.

[0066] The above embodiment has described an example where the sealed terminals 6 were attached, as small-diameter phase terminals, to the attachment holes 10 a. In the same manner as the case for the suction pipe 3 and the discharge pipe 4, the sealed terminals 6 may be attached to the attachment holes 10 a of the closed vessel 10 subjected to burring so that the pressure-resistant strength of the closed vessel 10 can be improved.

[0067] In this case, it is most preferable that the sealed terminals are formed as phase terminals. However, even if the prior-art three-phase integral type sealed terminal 5 is used, the attachment hole 10 a can be restrained from being deformed elliptically due to the barrel-like deformation of the closed vessel 10. Thus, the pressure-resistant strength of the closed vessel 10 is improved in comparison with the prior-art example.

[0068] Incidentally, a closed vessel 10 most excellent in pressure-resistant strength can be obtained by carrying out the following three, that is, the structure concerning the sealed terminals 6 and the method of attaching the sealed terminals 6 to the closed vessel 10 according to the invention, the method of attaching the suction pipe 3 to the closed vessel 10 according to the invention, and the method of attaching the discharge pipe 4 to the closed vessel 10 according to the invention. However, when any one or two of the three are carried out, a closed vessel 10 improved in pressure-resistant strength can be obtained.

[0069] In addition, the structure concerning the sealed terminals 6 and the method of attaching the sealed terminals 6 to the closed vessel 10 according to the invention, the method of attaching the suction pipe 3 to the closed vessel 10 according to the invention, and the method of attaching the discharge pipe 4 to the closed vessel 10 according to the invention, can be applied broadly not only to scroll compressors but also to other high pressure shell type compressors such as rotary compressors or screw compressors.

[0070] Further, the structure concerning the sealed terminals 6 and the method of attaching the sealed terminals 6 to the closed vessel 10 according to the invention, the method of attaching the suction pipe 3 to the closed vessel 10 according to the invention, and the method of attaching the discharge pipe 4 to the closed vessel 10 according to the invention, can be applied broadly to pressure-resistant vessels in the same manner as the closed vessel 10 for a compressor.

[0071] That is, sealed terminals for supplying three-phase electric power to an electric motor unit in a pressure-resistant vessel receiving the electric motor unit may be attached to the pressure-resistant vessel independently of one another, one for each phase. Thus, the strength of the pressure-resistant vessel and the strength of the attachment portions can be improved.

[0072] Further, in a pressure-resistant vessel having at least one of a pipe for introducing a fluid into the pressure-resistant vessel and a pipe for extracting the fluid from the pressure-resistant vessel, the pipe may be attached to an attachment hole formed in an attachment hole formation portion with a front end portion thereof subjected to burring. Thus, the strength of the pressure-resistant vessel and the strength of the attachment portion can be improved.

[0073] As described above, in the refrigerant compressor according to Claim 1 of the invention, three sealed terminals for supplying electric power to an electric motor of an electric motor unit are each attached to a closed vessel independently of one another for every phase.

[0074] Accordingly, the diameters of sealed terminal attaching holes are small, so that the strength against the deformation of the sealed terminals themselves is improved and the elliptic deformation of the sealed terminal attaching holes due to the barrel-like deformation of the closed vessel can be restrained to a minimum. Thus, an improvement is achieved in the strength of the sealed terminals, the strength of the attachment portions, and the strength of the closed vessel having the attachment portions to which the sealed terminals are attached. It is therefore possible to obtain a refrigerant compressor excellent in pressure-resistant strength and high in reliability.

[0075] Further, in the refrigerant compressor defined in Claim 2, the three phase terminals each attached to the closed vessel independently of one another for every phase are aligned substantially in a line in a circumferential direction of a body portion of the closed vessel.

[0076] Accordingly, cracking among the attachment holes can be restrained to a minimum. It is therefore possible to obtain a refrigerant compressor with sealed terminals and a closed vessel more excellent in pressure-resistant strength and higher in reliability.

[0077] In the refrigerant compressor defined in Claim 3, at least one of a suction pipe for sucking a refrigerant and a discharge pipe for discharging the refrigerant after compression is attached to an attachment hole formed in an attachment hole formation portion of a closed vessel with a front end portion thereof subjected to burring.

[0078] Accordingly, the strength of the attachment portion of the attachment hole is improved so that the elliptic deformation of the attachment portion of the attachment hole due to the barrel-like deformation of the closed vessel can be restrained. It is therefore possible to obtain a closed vessel with a suction pipe and a discharge pipe excellent in pressure-resistant strength and high in reliability, and hence to obtain a refrigerant compressor high in reliability.

[0079] In the refrigerant compressor defined in Claim 4, three sealed terminals for supplying electric power to an electric motor of an electric motor unit are each attached to a closed vessel independently of one another for every phase, while at least one of a suction pipe and a discharge pipe is attached to an attachment hole formed in an attachment hole formation portion of the closed vessel with a front end portion thereof subjected to burring.

[0080] Accordingly, it is possible to obtain a closed vessel with sealed terminals, a suction pipe and a discharge pipe excellent in pressure-resistant strength, and hence to obtain a refrigerant compressor high in reliability.

[0081] In the refrigerant compressor defined in Claim 5, at least one sealed terminal for supplying electric power to an electric motor of an electric motor unit is attached to an attachment hole formed in an attachment hole formation portion of a closed vessel with a front end portion thereof subjected to burring.

[0082] Accordingly, the strength of the attachment portion of the attachment hole is improved so that the elliptic deformation of the attachment portion of the attachment hole due to the barrel-like deformation of the closed vessel can be restrained. It is therefore possible to obtain a closed vessel with at least one sealed terminal excellent in pressure-resistant strength, and hence to obtain a refrigerant compressor high in reliability.

[0083] The pressure-resistant vessel defined in Claim 6 is a pressure-resistant vessel for receiving an electric motor unit, wherein sealed terminals for supplying three-phase electric power to the electric motor unit are each attached to the pressure-resistant vessel independently of one another for every phase. Accordingly, the strength of the pressure-resistant vessel and the strength of the attachment portion can be improved.

[0084] The pressure-resistant vessel defined in Claim 7 contains at least one of a pipe for introducing a fluid into the pressure-resistant vessel and a pipe for extracting the fluid from the pressure-resistant vessel, the pipe being attached to an attachment hole formed in an attachment hole formation portion of the pressure-resistant vessel with a front end portion thereof subjected to burring. Accordingly, the strength of the pressure-resistant vessel and the strength of the attachment portion can be improved. 

1. A refrigerant compressor of a high pressure shell system comprising: a compression mechanism unit for compressing a refrigerant; an electric motor unit; a drive shaft for transmitting driving power of said electric motor unit to said compression mechanism unit; and a closed vessel for receiving said compression mechanism unit, said electric motor unit and said drive shaft, a high pressure atmosphere being produced in said closed vessel by said compressed refrigerant; wherein three sealed terminals for supplying electric power to an electric motor of said electric motor unit are each attached to said closed vessel independently of one another for every phase.
 2. A refrigerant compressor according to claim 1, wherein said three phase terminals each attached to said closed vessel independently of one another for every phase are aligned substantially in a line in a circumferential direction of a body portion of said closed vessel.
 3. A refrigerant compressor of a high pressure shell system comprising: a compression mechanism unit for compressing a refrigerant; an electric motor unit; a drive shaft for transmitting driving power of said electric motor unit to said compression mechanism unit; and a closed vessel for receiving said compression mechanism unit, said electric motor unit and said drive shaft, a high pressure atmosphere being produced in said closed vessel by said compressed refrigerant; wherein at least one of a suction pipe for sucking said refrigerant and a discharge pipe for discharging said refrigerant after compression is attached to an attachment hole formed in an attachment hole formation portion of said closed vessel with a front end portion thereof subjected to burring.
 4. A refrigerant compressor of a high pressure shell system comprising: a compression mechanism unit for compressing a refrigerant; an electric motor unit; a drive shaft for transmitting driving power of said electric motor unit to said compression mechanism unit; and a closed vessel for receiving said compression mechanism unit, said electric motor unit and said drive shaft, a high pressure atmosphere being produced in said closed vessel by said compressed refrigerant; wherein three sealed terminals for supplying electric power to an electric motor of said electric motor unit are each attached to said closed vessel independently of one another for every phase, while at least one of a suction pipe for sucking said refrigerant and a discharge pipe for discharging said refrigerant after compression is attached to an attachment hole formed in an attachment hole formation portion of said closed vessel with a front end portion thereof subjected to burring.
 5. A refrigerant compressor of a high pressure shell system comprising: a compression mechanism unit for compressing a refrigerant; an electric motor unit; a drive shaft for transmitting driving power of said electric motor unit to said compression mechanism unit; and a closed vessel for receiving said compression mechanism unit, said electric motor unit and said drive shaft, a high pressure atmosphere being produced in said closed vessel by said compressed refrigerant; wherein at least one sealed terminal for supplying electric power to an electric motor of said electric motor unit is attached to an attachment hole formed in an attachment hole formation portion of said closed vessel with a front end portion thereof subjected to burring.
 6. A pressure-resistant vessel for receiving an electric motor unit, comprising: sealed terminals for supplying three-phase electric power to said electric motor unit, said sealed terminals being attached to said pressure-resistant vessel independently of one another, each for every phase.
 7. A pressure-resistant vessel comprising: at least one of a pipe for introducing a fluid into said pressure-resistant vessel and a pipe for extracting said fluid from said pressure-resistant vessel, said pipe being attached to an attachment hole formed in an attachment hole formation portion of said pressure-resistant vessel with a front end portion thereof subjected to burring. 